Prosocial tendencies (i.e., other oriented traits and behaviors focused on benefiting others, including sharing, helping, and empathy) are core aspects of social competence and an important marker of well-being and healthy adjustment (Carlo, 2006;Eisenberg &Fabes, 1998). Despite the evidence on the biological basis of prosocial tendencies, there is surprising little research on the personality correlates of prosociality (Eisenberg, Fabes, Karbon, Murphy, et al., 1996). Prior work has focused on a small number of fairly distinct temperamental correlates (e.g., sociability, negative emotionality, and self- regulation) of prosocial behavior and has had relatively mixed findings. Part of the reasons for the mixed findings may have to do with the fact that little attempt has been made to incorporate multiple temperamental dimensions in predicting prosocial dispositions and behavior. However, there is good reason to believe that temperamental dispositions do not work independently, but rather work together, to predict prosocial behavior. Thus, the aims of the proposed study are to: 1) identify groups of prosociality based on a cluster approach to temperament;2) examine the concurrent and longitudinal relations between temperament clusters and prosocial behaviors;and 3) examine whether these relations are moderated by demographic variables (gender, income, and ethnicity). We plan perform a cluster analyses (using 5 dimensions of temperament) in order to identify profiles of temperament that exist among a relatively diverse sample of 54-month-olds from the NICHD data base to predict prosocial behaviors both concurrently and in middle childhood (first and third grades). PUBLIC HEALTH RELEVANCE: The goal of this study is to examine how individual temperamental profiles predict prosocial behavior. It is important to understand the factors that predict prosocial behavior, because prosocial behavior is related to children's social competence and adjustment. Thus, children who are prosocial are less aggressive, have higher self- esteem, are better liked by peers, and are less depressed than children who are not prosocial.